Whether it is a new charge or a violation of parole, the destination is the same. SCI Phoenix is a Pennsylvania Department of Corrections facility, and both situations can result in someone being sent there to potentially serve out the remainder of their original sentence. The mechanism is different but the landing spot can be identical.
To find out which situation applies, there are a few ways to get that information before you talk to him directly.
The Pennsylvania court docket system is publicly accessible online at ujsportal.pacourts.us. You can search his name and pull up any active cases filed against him. If there is a new criminal charge, it will appear there as a new docket number with a different case filing. If it is purely a parole or probation violation, the action will appear on the existing case rather than as a new filing.
The Pennsylvania Department of Corrections inmate locator at cor.pa.gov will confirm his current facility and can sometimes indicate the reason for commitment, though that level of detail is not always available publicly.
You can also call the Pennsylvania Board of Probation and Parole if he was previously on parole, and ask whether a detainer or violation has been filed. They will confirm whether a violation is on record without giving you the full case details.
Once you can talk to him, he will know exactly what he is facing. But those public databases can give you a general picture before that call happens.
SCI Phoenix is a relatively new facility and one of the better Pennsylvania state prisons in terms of programming and conditions. That is worth knowing regardless of what brought him there.